Question: In which country is Dutch the official language?
Paraphrase: In which nation is Dutch the official dialect?
SPARQL (Wikidata):  select distinct ?sbj where { ?sbj wdt:P37 wd:Q7411 . ?sbj wdt:P31 wd:Q133156 } 
Answer: Belgian Congo, Cape Colony, New Netherland, Dutch Gold Coast, Dutch Virgin Islands, British Cape Colony, Dutch Cape Colony, Surinam